Torque wrench



' INVENTOR.

WLL/AM E. MN H0055 Dec. 12, 1967 mm \m w m w NW N w A, mm W m Q M i United States Patent 3,357,284 TORQUE WRENCH William E. Van Hoose, 4117 Brompton Ave., Bell, Calif. 90201 Filed Apr. 5, 1966, Ser. No. 540,277 12 Claims. (Cl. 8152.5)

This invention relates to a wrench adapted to indicate when a predetermined amount of torque pressure is attained and more particularly a wrench of the type wherein a predetermined torque pressure is indicated by the car ming of a resiliently mounted hearing which can be felt and heard by the user of the wrench as it moves.

Most conventional torque wrenches utilize indirect means for gauging the force applied to a given point. That is, various linkage elements are used between the gauge and the point being gauged. In use each additional bearing surface adds friction to the device and will cause wear and the wrench gradually loses its accuracy. Also, com plex linkage mechanisms between the gauges increase the cost of manufacture and multiply the number of potential defects in accuracy which may occur.

Therefore, it is an object of this invention to provide a torque wrench which provides a direct means for gauging the force applied thereby eliminating complex linkage mechanisms.

It is also an object of this invention to provide a torque wrench with a simple, inexpensive means for physically indicating when a predetermined torque pressure is reached.

In order to achieve these and other advantageous objects a wrench in accordance with this invention includes a resiliently mounted internal bearing element against which one end of a pivotally mounted lever bears in such a manner that it is cammingly engaged therewith. This lever is attached at its opposite end to a handle and the resilient mounting for the internal bearing is adjustable so that a predetermined amount of torque pressure is required to cam it relative to the lever. When cammed, a clicking sound occurs and a physically discernible movement can be felt in the handle. These indicia serve as torque pressure indicating means to the user of the wrench.

Other objects and advantages of this invention will become apparent from the following description and drawings wherein:

FIGURE 1 is a longitudinally sectioned side view of the subject torque wrench;

FIGURE 2 is a sectional view taken through 22 of FIGURE 1; and

FIGURE 3 is a partly fragmented top elevational view of a modified embodiment of the torque wrench.

The subject wrench generally is comprised of a hollow cylindrical main body 19 to which a torque transferring element in the form of rectangular adapter 12 is secured near one end thereof. Mounted within the other end of the main body 19 is a longitudinally extending shaft 14. A handle 16 is pivotally attached at an end of this shaft 14 which protrudes away from main body 10.

Adapter 12- extends through hollow main body normal to the axis thereof and is secured therein by an upper clip 18 and a lower clip 20 which are resiliently engaged on adapter 12 immediately adjacent the top and bottom, respectively, of main body 10. Adapter 12 depends down from the bottom of main body 10 and can be matingly engaged with a socket member 22 as shown in the drawings.

A helical compression spring 24 which is slightly smaller in diameter than the internal diameter of main body 10 extends logitudinally within main body It with one end bearing against the portion of adapter 12 that is within main body 10 in the form shown in FIGURES l and 2.

3,357,234 Patented Dec. 12, 1967 However, as shown in the modified form of FIGURE 3, which is a longer wrench, the compression spring 2411 need not extend until it abuts against adapter 12, which serves as a stop means, but can bear against an intermediate stop means or element 25 within the extended main body 10a.

The other end of spring 24 or 24a (the details of which only the former will be referred to hereinafter) abuts against a diametrically positioned fiat ring 26 which, in turn, forms a seat for and abuts a roller bearing in the form of a ball bearing 28 which is rotatably mounted within main body 10 and is just slightly smaller in diameter than the internal diameter of main body 10.

One end of a hollow cylindrical sleeve 30 is screwed onto the externally threaded end of main body 10 remote from adapter 12 and is axially aligned therewith. An externally threaded pivot seat 32 having a rounded circular center opening 33 is screwed in the opposite internally threaded end of sleeve 30. An end locking cap 34 is, in turn, secured over pivot seat 32 and bears against sleeve 30 to hold it in place.

Shaft 14 is, in effect, a handle lever and has an intermediate enlarged rounded bulge 36 adapted to be supported within the complementary rounded hole 33 of a pivot seat 32 so that a fulcrum is provided thereby. The forward portion 37 of shaft 14 is sufi'iciently smaller than the internal diameter of main body 10 that it can be moved therein as shown in the dotted lines in FIGURE 2. Extending from the forward end of shaft 14 are two spaced identical arms 38a and 38!) which protrude from one edge thereof between which a pin 40 is carried. On this pin 4i) concave roller 42 is mounted for rotatable movement and adapted to bear against bearing 28. The length of shaft 14 between fulcrum bulge 36 and the ends of arms 38a and 38b is suflicient that roller 42 can resiliently press against ball bearing 28 in a predetermined amount of camming engagement therewith.

A set screw 43 extends out from a complementary threaded hole in the forward portion 37 of shaft 41 just to the rear of arms 38a and 38b and on the side of shaft 14 adjacent to these arms. It is adapted to adjustably bear against the inside of main body 19 so that small variations can be made in the position where roller 40 contacts ball bearing 28. Normally, as best seen in FIGURE 2, engagement of roller 42 is slightly off of the center diameter of the ball bearing 28 so that when the wrench is turned so as to apply torque through adapter 12 roller 42 will cam up on top of bearing 28 (as shown in the dotted lines) when the predetermined torque pressure is attained.

Handle 16 is hollow and elliptically shaped for convenience in grasping. A pivot pin 44 extends centrally through its short diameter and also through the end of shaft 14 remote from adapter 12 so as to serve as the pivotal connection between the end of shaft 14 and handle 16. A horseshoe shaped keeper clip 46 resiliently snaps around shaft 14 adjacent to the rear of bulge 36 to hold it in place within pivot seat 32.

The rear outside of main bodies 10 and 10a are each marked with a longitudinally extending scale Stl as shown in FIGURE 3, which, in cooperation with a circumferential marking of a beveled forward outside edge 52 of sleeve 30, provides a gauge which predete-rmines the amount of torque which can be applied until roller 44 cams over ball bearing 28. That is, it can be seen that the amount of pressure required to produce the camming action depends upon the extent that spring 24 is compressed. Compression of spring 24, in turn, depends upon how far forward sleeve 30 is screwed relative to main body 10 or 10a since this presses roller 42 against bearing 28. This can be directly measured in foot-pound or inch-pound markings on 5% and 52. Set screw 43 can be adjusted to aid in initially calibrating the wrench or in compensating for wear which may affect the accuracy of the guage markings after a period of used.

In operation the form of the wrench shown in FIGURE 1 and in FIGURE 2 is to be used to apply torque by rotating a screw-type fastener clockwise. Thus, roller 42 is on the side of bearing 28 in the direction of rotation and will cam up on hearing 28 in a generally counterclockwise slipping motion to the position shown in dotted lnes when the predetermined torque limit pressure is exceeded. This slipping motion will be accompanied by a clicking or audible signal and a jerking movement which indicates to the user of the wrench that the torque pressure desired has been reached.

On the other hand if rotation of the wrench is desired to be counterclockwise in order to apply torque pressure, then the wrench is simply reversed by rotating the handle 16 from the position shown in FIGURE 2 so that roller 42 is on the opposite side of bearing 28 and camming movement will occur in a clockwise direction when the wrench is turned counterclockwise. Thus, it can be seen that roller 42 is on the side of bearing 28 that is in the direction the wrench is to be turned to apply torque pressure and that it rides up on top of bearing 28 in a movement opposite to the direction in which torque is being applied when the preset torque limit is reached.

While the particular torque wrenches herein shown and described in detail are fully capable of attaining the objects and providing the advantages hereinbefore mentioned, it is to be understood that these are merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. A torque wrench comprising an elongated hollow housing including a stop element and an axially adjustable fulcrum mounting therein, a torque transferring element secured to one end of said housing which is adapted to be turned on an axis normal to the axis of said housing, a handle lever pivotally mounted on said axially adjustable fulcrum mounting within said hollow housing that is located remote from said torque transferring element, said handle lever extending generally axially within said housing, a resilient element mounted within said housing, one end of which bears against said stop element therein at a location remote from the pivotal mounting of said handle lever, a bearing having camming sides sloping away from said handle lever and resiliently engaged by the end of said resilient element closer to said handle lever, 21 camming element on the end of said handle lever which is biased against a camming side of said bearing that is in the direction of rotation when said wrench is turned to apply torque and will ride up on top of said bearing under a predetermined amount of camming pressure causing an audible signal and a jerking movement of said handle, and means for varying the compression of said resilient element so as to be able to adjust the amount of predetermined camming pressure desired between said bearing and said camming element.

2. A torque wrench as defined in claim 1 wherein the elongated hollow housing is comprised of a main body to which the torque transferring element is secured at one end and at its opposite end an axially movable sleeve is secured thereto and the handle lever fulcrum is pivotally mounted in said axially movable sleeve so as to provide the means for varying the compression of the resilient element.

3. A torque wrench as defined in claim 2 wherein the bearing is round and the camming element is a roller carried by a pair of arms protruding from the end of the handle lever which is adjacent to said bearing.

4. A torque wrench as defined in claim 2 wherein the handle lever extends out from the axially movable sleeve and a handle is secured thereto remote from the engagement of its camming element with the bearing.

5. A torque wrench as defined in claim 2 wherein the resilient element is a helical spring.

6. A torque wrench comprising an elongated hollow main body, a torque transferring element secured to one end of said main body which is adapted to be turned on an axis normal to the axis of said main body, a stop means element within said main body, a resilient member mounted within said main body which bears against said stop means element and extends therein toward the end of said main body remote from said torque transferring element, a roller bearing mounted within said main body which bears against the end of said resilient member that is remote from said torque transferring element, an axially movable hollow sleeve adjustahly secured to the end of said main body remote from said torque transferring element and axially aligned with said main body, and a handle lever pivotally mounted at its fulcrum within said sleeve wherein a camming end of said lever extends generally axially within said sleeve and abuts said roller bearing therein and a handle end extends out from said sleeve, said handle lever having a camming element projecting from one edge of its camming end which bears against the side of said roller bearing that is in the direction of rotation when said wrench is turned to apply torque and which is adapted to resiliently cam up on top of said roller bearing with an audible signal and jerking physical movement when a predetermined torque limit is reached by said torque transferring element, wherein the predetermined torque limit is set by axially adjusting said sleeve thereby moving the fulcrum mounted handle lever to vary the amount of pressure between said roller bearing and the camming end of said handle lever.

7. A torque wrench as defined in claim 6 wherein the roller bearing is a ball bearing slightly smaller in diameter than the internal diameter of the main body and where the abutting camming element is a relatively small concave roller with an axis normal to the axis of the main body.

8. A torque wrench as defined in claim 6 wherein the resilient member is a helical spring axially aligned with the axis of the main body.

9. A torque wrench as defined in claim 6 wherein a handle is pivotally secured to the end of the handle lever remote from its abutment with the roller bearing.

10. A torque wrench as defined by claim 6 wherein torque is applied by the torque transferring element by rotation of the wrench in a clockwise direction and the camming element rolls up on top of the roller bearing in a counterclockwise movement when the predetermined torque limit is reached.

11. A torque wrench as defined by claim 6 wherein torque is applied by the torque transferring element by rotation of the wrench in a counterclockwise direction and the camming element rolls up on top of the roller bearing in a clockwise movement when the predetermined torque limit is reached.

12. A reversible torque limiting wrench adapted to be selectively turned either in a clockwise or counterclockwise direction when applying torque comprising an elongated hollow housing including a stop element and an axially adjustable fulcrum mounting therein, a torque transferring element secured to the end of said housing which is remote from said fulcrum mounting said torque transferring element adapted to be turned on an axis perpendicular to the axis of said hollow handle, a handle lever pivotally mounted on said axially adjustable fulcrum mounting, one end of which extends into said hollow housing and the other end protruding from said hollow handle, a resilient element within said housing which bears against said stop element therein and extends toward said handle element, a bearing resiliently mounted on the end of said resilient element which is closer to said handle lever, said bearing having an upper surface adjacent to said handle lever and a first camrning surface and a second carnrning surface which slope away from said upper surface on each side of said upper surface wherein said first camrning surface is forward when the wrench is rotated clockwise and said second camming surface is forward when the wrench is rotated counterclockwise, a carnming element on the end of said handle lever adjacent to said bearing, said camming element being offset from the axis of said handle lever and resiliently biased against the first camming surface of said bearing when torque is to be applied clockwise and against the second camming surface of said bearing when torque is to be applied counterclockwise, wherein a predetermined torque limit is indicated by an audible sound and jerking physical movement in said handle lever caused by pivoting thereof and said camming element sliding up to the upper surface of said bearing in a counterclockwise direction from said first camming surface when torque is applied clockwise and sliding up in a clockwise direction from said second camming surface when torque is applied counterclockwise, and wherein the predetermined torque limit is set by axially adjusting said fulcrum mounting of said hollow handle thereby varying the amount of resilient pressure between said bearing and said camming element.

References Cited UNITED STATES PATENTS 2,300,652 11/1942 Cooney 81--52.5 2,918,834 12/1959 Cranford 8152.4 2,959,078 11/1960 Skidrnore 81-52.4 3,016,773 1/1962 Woods 8 l52.4

JAMES L, JONES, JR., Primary Examiner. 

1. A TORQUE WRENCH COMPRISING AN ELONGATED HOLLOW HOUSING INCLUDING A STOP ELEMENT AND AN AXIALLY ADJUSTABLE FULCRUM MOUNTING THEREIN, A TORQUE TRANSFERRING ELEMENT SECURED TO ONE END OF SAID HOUSING WHICH IS ADAPTED TO BE TURNED ON AN AXIS NORMAL TO THE AXIS OF SAID HOUSING, A HANDLE LEVER PIVOTALLY MOUNTED ON SAID AXIALLY ADJUSTABLE FULCRUM MOUNTING WITHIN SAID HOLLOW HOUSING THAT IS LOCATED REMOTE FROM SAID TORQUE TRANSFERRING ELEMENT, SAID HANDLE LEVER EXTENDING GENEALLY AXIALLY WITHIN SAID HOUSING, A RESILIENT ELEMENT MOUNTED WITHIN SAID HOUSING, ONE END OF WHICH BEARS AGAINST SAID STOP ELEMENT THEREIN AT A LOCATION REMOTE FROM THE PIVOTAL MOUNTING OF SAID HANDLE LEVER, A BEARING HAVING CAMMING SIDES SLOPING AWAY FROM SAID HANDLE LEVER AND RESILIENTLY ENGAGED BY THE END OF SAID RESILIENT ELEMENT CLOSER TO SAID HANDLE LEVER, A CAMMING ELEMENT ON THE END OF SAID HANDLE LEVER 